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Improved "decoder_trigger" handling

This commit is contained in:
Clifford Wolf 2015-06-07 19:49:38 +02:00
parent bbbcea2faa
commit 8e3e0bfba0
1 changed files with 11 additions and 14 deletions
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25
picorv32.v
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@ -160,6 +160,7 @@ module picorv32 #(
reg [regindex_bits-1:0] decoded_rd, decoded_rs1, decoded_rs2;
reg [31:0] decoded_imm;
reg decoder_trigger;
reg decoder_pseudo_trigger;
wire [31:0] decoded_imm_uj;
assign { decoded_imm_uj[31:20], decoded_imm_uj[10:1], decoded_imm_uj[11], decoded_imm_uj[19:12], decoded_imm_uj[0] } = $signed({mem_rdata[31:12], 1'b0});
@ -250,8 +251,6 @@ module picorv32 #(
end
always @(posedge clk) begin
decoder_trigger <= 0;
if (mem_do_rinst && mem_done) begin
instr_lui <= mem_rdata[6:0] == 7'b0110111;
instr_auipc <= mem_rdata[6:0] == 7'b0010111;
@ -308,11 +307,9 @@ module picorv32 #(
decoded_rd <= mem_rdata[11:7];
decoded_rs1 <= mem_rdata[19:15];
decoded_rs2 <= mem_rdata[24:20];
decoder_trigger <= 1;
end
if (decoder_trigger) begin
if (decoder_trigger && !decoder_pseudo_trigger) begin
(* parallel_case *)
case (1'b1)
|{instr_lui, instr_auipc}:
@ -351,8 +348,6 @@ module picorv32 #(
reg set_mem_do_rinst;
reg set_mem_do_rdata;
reg set_mem_do_wdata;
reg mask_decoder_trigger;
reg force_decoder_trigger;
reg latched_store;
reg latched_stalu;
@ -411,14 +406,15 @@ module picorv32 #(
set_mem_do_rinst = 0;
set_mem_do_rdata = 0;
set_mem_do_wdata = 0;
mask_decoder_trigger <= 0;
force_decoder_trigger <= 0;
reg_alu_out <= alu_out;
if (ENABLE_COUNTERS)
count_cycle <= resetn ? count_cycle + 1 : 0;
decoder_trigger <= mem_do_rinst && mem_done;
decoder_pseudo_trigger <= 0;
if (!resetn) begin
reg_pc <= 0;
reg_next_pc <= 0;
@ -440,7 +436,7 @@ module picorv32 #(
trap <= 1;
end
cpu_state_fetch: begin
mem_do_rinst <= (!decoder_trigger || mask_decoder_trigger) && !force_decoder_trigger;
mem_do_rinst <= !decoder_trigger;
mem_wordsize <= 0;
current_pc = reg_next_pc;
@ -470,7 +466,7 @@ module picorv32 #(
latched_is_lb <= 0;
latched_rd <= decoded_rd;
if ((decoder_trigger && !mask_decoder_trigger) || force_decoder_trigger) begin
if (decoder_trigger) begin
`ifdef DEBUG
$display("DECODE: 0x%08x %-s", current_pc, instruction);
`endif
@ -560,7 +556,7 @@ module picorv32 #(
if (alu_out_0) begin
latched_store <= 1;
latched_branch <= 1;
mask_decoder_trigger <= 1;
decoder_trigger <= 0;
set_mem_do_rinst = 1;
end
end else begin
@ -608,7 +604,7 @@ module picorv32 #(
end
if (!mem_do_prefetch && mem_done) begin
cpu_state <= cpu_state_fetch;
force_decoder_trigger <= 1;
decoder_trigger <= 1;
end
end
end
@ -635,7 +631,8 @@ module picorv32 #(
latched_is_lh: reg_out <= $signed(mem_buffer[15:0]);
latched_is_lb: reg_out <= $signed(mem_buffer[7:0]);
endcase
force_decoder_trigger <= 1;
decoder_trigger <= 1;
decoder_pseudo_trigger <= 1;
cpu_state <= cpu_state_fetch;
end
end